But Mr Hislop had a serious message for inquiry chairman Lord Justice Leveson. "Statutory regulation is not required," he said, pointing out that phone-hacking and paying police officers were already illegal.

He pointed the finger at newspapers' relationships with police and politicians, saying News International was so "deeply embedded" that the proprietor's wife had been invited to "slumber parties" at the prime ministerial retreat Chequers.

It was the Press Complaints Commission that felt the ire of Alan Rusbridger, editor of the Guardian, whose revelations about conduct at the News of the World triggered the inquiry.

Media captionMr Wallace said that hacking could have been the source of the Ulrika Jonsson story

The week had begun with the reading of a letter from former Prime Minister Gordon Brown, denying claims he had threatened to "destroy" News International during a call to Rupert Murdoch after the Sun switched political allegiance.

Harding argued some intrusion was in the public interest, quoting the publication of Adam Werritty's bank details during an investigation into the level of access he had to former Defence Secretary Liam Fox.

Sunday Times editor John Witherow called phone hacking "illegal and unethical" and said it had never happened on his paper, although he had employed private detectives.